阅读说明：本技术 一种用于车辆的风噪控制方法及装置 (Wind noise control method and device for vehicle ) 是由 沐永生 马登永 叶超 蔡野锋 于 2020-06-15 设计创作，主要内容包括：本发明公开了一种用于车辆的风噪控制方法及装置。一种用于车辆的风噪控制方法,包括如下步骤：S1、实时或定时对车窗开度信息进行采样；S2、根据所述车窗开度信息计算车厢和车窗形成的亥姆霍兹共鸣器的固有频率；S3、根据所述固有频率确定是否产生了风振噪声模态标志信号,当所述风振噪声模态标志信号产生,执行下述步骤S4；S4、根据所述固有频率产生参考信号,并根据所述参考信号及车内的噪声信号更新滤波器参数,输出稳定的控制信号；及S5、根据所述稳定的控制信号驱动扬声器产生主动控制声场,并与噪声场相干叠加。本发明采用主动降噪方式解决风振噪声,车辆结构不需过多改动。(The invention discloses a wind noise control method and device for a vehicle. A wind noise control method for a vehicle, comprising the steps of: s1, sampling the car window opening information in real time or at regular time; s2, calculating the natural frequency of a Helmholtz resonator formed by the carriage and the window according to the window opening information; s3, determining whether a wind vibration noise mode flag signal is generated according to the natural frequency, and executing the following step S4 when the wind vibration noise mode flag signal is generated; s4, generating a reference signal according to the natural frequency, updating filter parameters according to the reference signal and a noise signal in the vehicle, and outputting a stable control signal; and S5, driving the loudspeaker to generate an active control sound field according to the stable control signal, and coherently superposing with the noise field. The invention adopts an active noise reduction mode to solve wind vibration noise, and the vehicle structure does not need to be changed too much.)

1. A wind noise control method for a vehicle, characterized by comprising the steps of:

s1, sampling the car window opening information in real time or at regular time;

s2, calculating the natural frequency of a Helmholtz resonator formed by the carriage and the window according to the window opening information;

s3, determining whether a wind vibration noise mode flag signal is generated according to the natural frequency, and executing the following step S4 when the wind vibration noise mode flag signal is generated;

s4, generating a reference signal according to the natural frequency, updating filter parameters according to the reference signal and a noise signal in the vehicle, and outputting a stable control signal; and

and S5, driving the loudspeaker to generate an active control sound field according to the stable control signal, and performing coherent superposition with the noise field.

2. The wind noise control method according to claim 1, wherein the step S4 specifically includes the steps of:

s41, calculating the natural frequency according to the sampled window opening information, and generating a reference signal according to the natural frequency;

s42, generating a control signal according to the reference signal and the filter parameter;

s43, obtaining an error signal according to the control signal and a noise signal obtained by real-time or timing detection;

s44, updating filter parameters according to the error signal and the filter reference signal;

wherein, the above steps S41 to S44 are repeated until the filter parameter is not updated any more, and the stable control signal is output.

3. The wind noise control method according to claim 2, wherein in step S41, a sine signal or a cosine signal is constructed as the reference signal according to the natural frequency; in step S42, the control signal is generated by the following equation: Y-W X, wherein Y denotes a control signal, W denotes a filter parameter, and X denotes a reference signal; in step S43, the error signal is generated by: E-D-Y, where E denotes an error signal, D denotes a noise signal, and Y denotes a control signal.

4. The wind noise control method according to claim 2, wherein in step S44, the filter parameter is updated according to the following formula:where W denotes the filter parameters, μ is the convergence factor, E denotes the error signal,

the filtered reference signal

5. The wind noise control method according to claim 4, further comprising the step of initializing a filter parameter W, wherein W ═ W₁(n)…w_L(n)]^T，w_i(n)＝[w_i(n)…w_i(n-J)]^TN represents the number of shear wave modes, L represents the number of loudspeakers, i is more than or equal to 1 and less than or equal to L, and J represents the length of the filter parameter.

6. The wind noise control method according to claim 1, wherein in the step S3,

generating the wind vibration noise modal signature signal when the natural frequency in the cabin is comparable to a vortex shedding frequency; or the like, or, alternatively,

and generating a reference signal according to the natural frequency, carrying out constant coherence analysis on the reference signal and a noise signal detected in real time or at regular time, and generating the wind vibration noise modal marker signal when a constant coherence coefficient is greater than or equal to a set value.

7. The wind noise control method according to claim 1, further comprising a step of clearing the wind vibration noise mode flag signal when a vehicle speed of a vehicle is lower than a set vehicle speed, a window is closed, or a door is opened.

8. The wind noise control method according to any one of claims 1 to 7, wherein in step S1, the window opening information is acquired by an on-vehicle communication protocol.

9. The wind noise control method according to any one of claims 1 to 7, wherein the speakers include a woofer unit of an in-vehicle door panel speaker and a subwoofer unit of a rear row; the noise signal is acquired by a microphone, which is disposed at least at the riding position.

10. A wind noise control apparatus for a vehicle for executing the wind noise control method according to any one of claims 1 to 9, characterized by comprising:

the communication module is used for acquiring the car window opening information;

the reference signal generating module is used for calculating the natural frequency of a Helmholtz resonator formed by a carriage and a vehicle window according to the vehicle window opening information and generating a reference signal according to the natural frequency;

the active noise reduction enabling module is used for determining whether a wind vibration noise modal marker signal is generated or not according to the inherent frequency and the eddy current divergence frequency or the reference signal and the noise signal and sending an enabling signal after the wind vibration noise modal marker signal is generated;

the adaptive filter is used for filtering the reference signal to output a control signal after receiving the enabling signal, and adjusting the coefficient of the filter along with the noise signal;

the digital-to-analog conversion module is used for converting the control signal into an analog signal;

the reconstruction filter is used for filtering the analog signal output by the digital-to-analog conversion module;

the power amplification module is used for carrying out power amplification on the analog signal output by the reconstruction filter;

the loudspeaker is driven by the power amplification module to convert the electric signal into an acoustic signal, and the acoustic signal is replayed in the carriage to generate an active control sound field which is coherently superposed with a noise field; and

and the sound acquisition device is used for acquiring noise signals in the carriage.

Technical Field

The invention belongs to the technical field of vehicle noise reduction, and relates to a wind noise control method and device for a vehicle.

Background

Noise is a key issue in automotive NVH (Noise, virtualization, Harshness). Active control is currently applied in automobiles to reduce noise in the automobile to become a hotspot. Current research is primarily concerned with the problem of noise control in sealed vehicles. However, in an actual driving environment, a driver and a passenger in the vehicle often open a window to ventilate, and at this time, a relatively obvious noise is generated, which is called wind vibration noise (wind noise), and is referred to as wind noise for short.

The principle of wind vibration noise is as follows: when the window is opened, a cavity is formed in the carriage; when the automobile runs at a high speed, a shear layer is formed between airflow flowing through the outside of the automobile at a high speed and relatively static air in the automobile; the shear layer can periodically form vortex and diffuse, and along with backward movement of the airflow, the shear layer impacts the rear edge of the window opening to be crushed, and pressure waves diffused all around are generated; when the diffusion frequency of the vortex is consistent with the natural vibration frequency of the air in the carriage, namely the characteristic mode, Helmholtz resonance occurs, and then wind vibration noise is formed.

At present, wind vibration noise caused by opening a vehicle window is not suppressed too much. The main inhibiting means is to guide the vortex to leave through the slotted wind guide strip. However, the design of the wind guide strip is difficult to complete, and especially the size change of the opening and closing of the car window is often unpredictable, so that all problems are difficult to solve through the wind guide strip in a fixed mode.

There is less relevant literature on active control of noise caused by window opening. Patent document CN107195294, although providing an active noise reduction method and device for a vehicle, is directed to active control of the ambient noise that propagates through the open window to the inside and outside of the vehicle, which reduces the ambient noise outside of the vehicle. The wind vibration noise is different from the environment noise outside the vehicle, and the wind vibration noise is not the environment noise outside the vehicle, but is generated in the carriage due to the Helmholtz resonance principle and is also different from the wind noise in the general sense.

Disclosure of Invention

In view of the above technical problems, an object of the present invention is to provide a method and an apparatus for controlling wind noise of a vehicle, which solve wind vibration noise by an active noise reduction method without modifying the vehicle structure too much.

To achieve the above object, an aspect of the present invention provides a wind noise control method for a vehicle, including the steps of:

s1, sampling the car window opening information in real time or at regular time;

s2, calculating the natural frequency of a Helmholtz resonator formed by the carriage and the window according to the window opening information;

s3, determining whether a wind vibration noise mode flag signal is generated according to the natural frequency, and executing the following step S4 when the wind vibration noise mode flag signal is generated;

s4, generating a reference signal according to the natural frequency, updating filter parameters according to the reference signal and a noise signal in the vehicle, and outputting a stable control signal; and

and S5, driving the loudspeaker to generate an active control sound field according to the stable control signal, and performing coherent superposition with the noise field.

Preferably, the step S4 specifically includes the following steps:

s41, calculating the natural frequency according to the sampled window opening information, and generating a reference signal according to the natural frequency;

s42, generating a control signal according to the reference signal and the filter parameter;

s43, obtaining an error signal according to the control signal and a noise signal obtained by real-time or timing detection;

s44, updating filter parameters according to the error signal and the filter reference signal;

wherein, the above steps S41 to S44 are repeated until the filter parameter is not updated any more, and the stable control signal is output.

More preferably, in step S41, a sine signal or a cosine signal is constructed as the reference signal according to the natural frequency.

More preferably, in step S42, the control signal is generated by the following equation: Y-W X, where Y denotes the control signal, W denotes the filter parameters, and X denotes the reference signal.

More preferably, in step S43, the error signal is generated by the following equation: E-D-Y, where E denotes an error signal, D denotes a noise signal, and Y denotes a control signal.

More preferably, in step S44, the filter parameter is updated according to the following formula:where W denotes the filter parameters, μ is the convergence factor, E denotes the error signal,represents a filter reference signal;

the filtered reference signalProduced by the formula:wherein S represents a transfer function of each speaker to the corresponding sound collection device, and X represents a reference signal. The sound collection device may be a microphone.

Further, the wind noise control method further includes the step of initializing a filter parameter W, where W ═ W₁(n)…w_L(n)]^T，w_i(n)＝[w_i(n)…w_i(n-J)]^TN represents the number of shear wave modes, L represents the number of loudspeakers, i is more than or equal to 1 and less than or equal to L, and J represents the length of the filter parameter.

In a preferred embodiment, in the step S3, the wind vibration noise mode flag signal is generated when the natural frequency in the cabin is equivalent to the vortex dispersion frequency.

Preferably, the natural frequency f is calculated according to:

wherein c is the speed of sound, which is a constant; a is the sectional area of the neck of the Helmholtz resonator, namely the opening area of the opened car window; v is the volume of the Helmholtz resonator, namely the volume of the carriage, and can be measured; l is the length of Helmholtz resonator neck, namely the thickness distance between door outline and the interior trim part inward flange, can measure and obtain.

More preferably, the frequency f of the eddy current divergence is calculated according to the following formula_b：

Where u is the incoming flow velocity, i.e., vehicle speed in general; n is the number of shear wave modes, and n is 1,2, 3; l is_nIs the skylight opening.

In another preferred embodiment, in step S3, a reference signal is generated according to the natural frequency, the reference signal is subjected to a constant coherence analysis with a noise signal detected in real time or at regular time, and the wind vibration noise mode flag signal is generated when the constant coherence coefficient is greater than or equal to a set value.

More preferably, the formula of the normally coherent analysis is as follows

Wherein G is_xyIs the cross-power spectrum of both signals; g_xxIs the self-power spectrum of the reference signal x (n); g_yyIs the self-power spectrum of the noise signal d (n). Current constant coherence coefficient C_xyGreater than or equal to 0.9 indicates that a target noise signal is generated, thereby generating a wind vibration noise mode flag signal.

Preferably, the wind noise control method further comprises a step of clearing the wind vibration noise mode flag signal, and the wind vibration noise mode flag signal is cleared when the vehicle speed of the vehicle is lower than a set vehicle speed, the vehicle window is closed or the vehicle door is opened.

Preferably, in step S1, the window opening information is acquired through an onboard communication protocol.

More preferably, the speakers include a woofer unit of a vehicle door panel speaker and a subwoofer unit of a rear row.

More preferably, the noise signal is acquired by a microphone, which is disposed at least at the riding position.

Another aspect of the present invention provides a wind noise control apparatus for a vehicle, including:

the communication module is used for acquiring the car window opening information;

the reference signal generating module is used for calculating the natural frequency of a Helmholtz resonator formed by a carriage and a vehicle window according to the vehicle window opening information and generating a reference signal according to the natural frequency;

the active noise reduction enabling module is used for determining whether a wind vibration noise modal marker signal is generated or not according to the inherent frequency and the eddy current divergence frequency or the reference signal and the noise signal and sending an enabling signal after the wind vibration noise modal marker signal is generated;

the adaptive filter is used for filtering the reference signal to output a control signal after receiving the enabling signal, and adjusting the coefficient of the filter along with the noise signal;

the digital-to-analog conversion module is used for converting the control signal into an analog signal;

the reconstruction filter is used for filtering the analog signal output by the digital-to-analog conversion module;

the power amplification module is used for carrying out power amplification on the analog signal output by the reconstruction filter;

the loudspeaker is driven by the power amplification module to convert the electric signal into an acoustic signal, and the acoustic signal is replayed in the carriage to generate an active control sound field which is coherently superposed with a noise field; and

and the sound acquisition device is used for acquiring noise signals in the carriage.

Compared with the prior art, the invention has the following advantages by adopting the scheme:

according to the invention, the wind vibration noise of the vehicle is reduced by adopting an active noise reduction mode, automobile accessories such as wind guide strips and the like do not need to be additionally developed, and an active noise reduction control system can be built only by utilizing a loudspeaker playback system of an automobile door plate, so that the active noise reduction control system has higher integration level; the development cost is lower, and the development period and the debugging period are shorter; the automobile can be functionally added after the automobile is shaped, and the requirement on the change of automobile development is low.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a schematic diagram of a wind noise control method according to an embodiment of the present invention;

fig. 2 is a block diagram of a wind noise control apparatus according to an embodiment of the present invention.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that the advantages and features of the invention may be more readily understood by those skilled in the art. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto.

The present embodiment provides a wind noise control method for a vehicle, which will be described in detail below with reference to fig. 1.

Firstly, determining the position of a microphone.

The microphones are arranged according to the distribution of the noise field. The microphone arrangement is based on: the position noise field has large amplitude; the sound radiation response gain from the door panel loudspeaker to the microphone is large, and amplitude response valley points cannot be formed under the influence of a carriage sound field mode; the position is closer to the ears of the driver and the passengers, and the distance is less than 1/10 wavelengths of noise frequency; the engineering installation is operable.

And secondly, determining the number of the microphones.

And determining M microphones according to the noise reduction requirement. The noise reduction requirements are what locations need to be processed. In the present embodiment, M microphones are provided at M riding locations, and at least one microphone is provided at each riding location.

And thirdly, determining the number of the loudspeakers.

And selecting the number L of the loudspeakers according to the performance and the configuration of the loudspeakers of the vehicle-mounted door panel. The acoustic radiation performance of some speakers to the target location does not meet the noise reduction requirements and is discarded. In the present embodiment, L speaker units are constituted by four door panel woofer units and a rear row subwoofer unit, which is also referred to as a secondary sound source in the present embodiment.

And fourthly, acquiring the opening area A of the car window in real time.

The window opening area A is acquired in real time according to an onboard communication protocol, such as CAN communication. The CAN communication CAN directly contain the car window opening information; or estimating the formation of the window glass according to the command cycle of opening and closing the window and the rotating speed of the lifting motor in the CAN communication protocol, and further estimating the window opening area A.

And fifthly, acquiring the vehicle speed u in real time.

And acquiring the vehicle speed information in real time according to a vehicle-mounted listening communication protocol, such as CAN communication.

And sixthly, calculating the natural frequency f of a Helmholtz resonator formed by the carriage and the vehicle window.

Calculated according to the following formula:

wherein c is the speed of sound, which is a constant; a is the sectional area of the neck of the Helmholtz resonator, namely the opening area of the opened car window; v is the volume of the Helmholtz resonator, namely the volume of the carriage, and can be measured; l is the length of Helmholtz resonator neck, namely the thickness distance between door outline and the interior trim part inward flange, can measure and obtain.

Seventhly, calculating the eddy current divergence frequency f_b。

Calculated according to the following formula:

where u is the incoming flow velocity, i.e., vehicle speed in general; n is the number of shear wave modes, and n is 1,2, 3; l is_nIs the skylight opening.

And eighthly, determining a wind vibration noise modal marker signal.

The following two methods are used for determining the wind vibration noise modal signature:

1. according to the steps, when the natural frequency f and the vortex divergence frequency f of the air in the compartment_bRather, wind vibration noise is generated, and therefore a wind vibration noise mode flag signal is generated.

2. From the natural frequency f estimated in step six, a sine wave signal, also called reference signal x (n), is constructed. And carrying out constant coherence analysis on the reference signal and a noise signal d (n) obtained by detecting the microphone in real time. The formula of the ordinary coherence analysis is as follows

Wherein G is_xyIs the cross-power spectrum of both signals; g_xxIs the self-power spectrum of the reference signal x (n); g_yyIs the self-power spectrum of the noise signal d (n). Current constant coherence coefficient C_xyGreater than or equal to 0.9 indicates that a target noise signal is generated, thereby generating a wind vibration noise mode flag signal.

And ninthly, starting the active noise reduction function.

And once the wind vibration noise modal marker signal is detected, starting the active noise reduction function. The method comprises the following specific steps:

1. measuring a secondary channel transfer function S, i.e. the acoustic radiation response from each secondary sound source to each monitoring microphone, whereins_mlRefers to the transfer function between the mth monitoring microphone and the lth secondary sound source, where M is 1,2, … M; 1,2, … L; forming a matrix by transfer functions among the channels, and recording the matrix as S;

2. initialQuantizing the filter parameter W, wherein W ═ W₁(n)…w_L(n)]^T，w_i(n)＝[w_i(n)…w_i(n-J)]^TJ is the length of the filter parameters, generally above 2, and if the adaptive notch filter is used, the length of the filter is 2;

3. generating a reference signal X, wherein X ═ X (n) … X (n-J)]^T(ii) a Constructing a sine signal or a cosine signal according to the natural frequency f obtained by calculation at each sampling moment;

4. generating a control signal Y, W X;

5. obtaining an error signal E, E ═ D-Y, where D ═ D₁(n)…d_M(n)]^T；d_mIs the noise signal of the spatial position of the mth monitoring microphone, wherein M is 1,2, … M; noise signals at all monitoring positions form an array (or vector) and are recorded as D;

6. obtaining a filtered reference signalWherein

7. The filter parameters W are updated and the filter parameters W,

wherein mu is a convergence factor, is a constant, is the least mean square adaptive algorithm, and can also be a parameter changing along with time, is the variable step length least mean square adaptive algorithm;

8. and returning to the step 3, and repeating the steps until the error signal E is smaller and the filter parameter W is not updated any more to obtain a stable control effect.

And tenth, clearing the wind vibration noise mark signal.

The flag signal is cleared by detecting that the vehicle speed is low, the window is closed, the door is open, or the like, through an in-vehicle communication protocol such as CAN communication.

After the ignition of the automobile is started, the mark signal keeps a clearing state.

The present embodiment also provides a wind noise control apparatus for a vehicle that executes the above-described wind noise control method. Referring to fig. 2, the wind noise control apparatus for a vehicle includes:

the communication module is used for acquiring the car window opening information;

the reference signal generating module is used for calculating the natural frequency of a Helmholtz resonator formed by a carriage and a vehicle window according to the vehicle window opening information and generating a reference signal according to the natural frequency;

the active noise reduction enabling module is used for determining whether a wind vibration noise modal marker signal is generated or not according to the inherent frequency and the eddy current divergence frequency or the reference signal and the noise signal and sending an enabling signal after the wind vibration noise modal marker signal is generated;

the adaptive filter is used for filtering the reference signal to output a control signal after receiving the enabling signal, and adjusting the coefficient of the filter along with the noise signal;

the digital-to-analog conversion module is used for converting the control signal into an analog signal;

the reconstruction filter is used for filtering the analog signal output by the digital-to-analog conversion module;

the power amplification module is used for carrying out power amplification on the analog signal output by the reconstruction filter;

the loudspeaker is driven by the power amplification module to convert the electric signal into an acoustic signal, and the acoustic signal is replayed in the carriage to generate an active control sound field which is coherently superposed with a noise field; and

and the sound acquisition device is used for acquiring noise signals in the carriage.

The communication module is specifically a CAN communication module, and is communicated with an automobile host to acquire information such as automobile speed, automobile door opening and closing, automobile window opening and closing states, automobile window opening and closing commands and the like, and the information is transmitted to the active noise reduction enabling module and the reference signal generating module in real time.

The reference signal generation module is specifically a sine signal generation module, and obtains the opening and closing degree of the car window according to the car window opening and closing information obtained by the CAN information, so that the resonance frequency of the air in the carriage is calculated, and a sine wave signal of the frequency is constructed.

When the automobile is ignited and started, the active noise reduction enabling module ensures that the active noise reduction enabling module is closed, namely, the active noise reduction function is closed; when the detection car door is closed, the car window is opened, and the car speed meets the condition that the vortex divergence modal frequency is the same as the resonance frequency of air in the car; or the constant coherence coefficient of the sinusoidal signal and the noise signal is greater than 0.9; in both cases, wind vibration noise can be considered to be generated, and an enabling signal is sent out, so that the active noise reduction function is enabled.

The adaptive filter starts to work under the action of the enabling signal. The sine signal generating module is used for generating a sine signal, and the sine signal is filtered to output a control signal after the amplitude and the phase are adjusted; the second is self-adaptation, in which the coefficient of the filter is gradually adjusted along with the magnitude of the noise signal, and when the noise signal is 0 or slightly close to 0, the coefficient of the filter stops updating.

The digital-to-analog conversion module converts the digital signal output by the adaptive filter into an analog signal.

The reconstruction filter is a filter formed by an analog circuit, and filters quantization noise and the like contained in high-frequency out-of-band signals and digital signals, so that noise is prevented from being generated, and even the control effect of active noise reduction is influenced.

The power amplification module carries out a power method on the analog control signal so as to drive the loudspeaker unit.

The loudspeaker converts the electric signal into the acoustic signal, reproduces the acoustic signal in the carriage to generate an active control sound field, and is coherently superposed with the original noise field. The door panel loudspeaker and the subwoofer loudspeaker units with sound radiation performance meeting the requirements are selected, and the door panel loudspeaker and the subwoofer loudspeaker units have good frequency response characteristics in a target noise reduction frequency band;

the microphone collects noise signals in a carriage in real time, wherein the noise signals comprise original noise signals and noise field residual noise signals after active control; the microphone needs to be installed near the target noise reduction area, i.e., near the head or ear of the occupant.

Compared with a passive mode, the active noise reduction method does not need to additionally develop automobile accessories such as air guide strips and the like, and only needs to utilize a speaker playback system of an automobile door plate to build an active noise reduction control system. The active control system has a higher degree of integration. Compared with a passive method, the method has the advantages of lower development cost, shorter development period and debugging period. Passive methods require planning and even modification of the structure and appearance of the vehicle at an early stage of vehicle development. However, the active control method can be used for functional addition after the automobile is shaped, and the requirement on the change of automobile development is low.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and are preferred embodiments, which are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.